This invention is in the field of self-contained hydraulic power supply units and more particularly a self-propelled hydraulic power supply and tool mounting platform.
Portable concrete slab saws are often utilized in making cuts and modifications to previously formed and hardened concrete and asphalt. Such portable slab saws are necessary to make the vertically oriented cuts in street paving for the redefinition of street boundaries and curb lines as well as for maintenance procedures on expansion joints in concrete slabs. These saws are also frequently used in cutting trenches in concrete for cable and pipe laying in both streets and in new building construction or renovation, and they are especially useful wherever it is desired to obtain a cut with a relatively smooth kerf line rather than a cut with the very rough edges given by pneumatic or hydraulically powered breakers or hammers.
A major cost incurred in the slab sawing or concrete is the cost of saw blade replacement. The frequency of blade replacement is dictated by many things, but an important one among them is the amount of vibration introduced to the spinning blade by the engine and drive belts or chains. The more vibration that is transmitted to the blade by an engine and drive mechanism, the more rapid the destructive wear that takes place on the diamond-cutting matrix of the blade. The slab saws in current use do not operate at an optimum cost efficiency because of this excessive destructive vibration introduced to the blades, hence, cost for replacing the blade and downtime of the equipment can become excessive. The prior portable saw device, being relatively light for handling purposes, does not serve as a sufficiently steady and firm platform for the blade, thus permitting excessive vibration of the blade and attendant excessive saw blade wear and occasional blade breakage.
Long, relatively deep, cuts are often made in concrete for expansion joints or to form utility trenches so that cables or pipes can be laid. Obtaining a long, deep cut on a predesignated line with a minimum of roughness to the cut edges is a feat that current versions of the self-propelled slab saw are often unable to perform. Prior portable devices, being relatively light and with excessive vibration for handling purposes are easily deflected from the intended course of travel, with possible damage to the saw blade as its path of travel is altered while deeply inserted within the kerf.
The results of the vibration inherent in current versions of slab saws can be greatly reduced when the saw blade is driven by a hydraulic motor and when attached to a heavy secure, vibration-resistant tool mount. The power supply comprising a hydraulic motor, driven by a hydraulic pump and in turn driven by a gasoline engine has much less vibration applied to the saw blade than the power supply consisting of a direct drive or a drive through belts or chains from a gaoline engine.
Hydraulic power supplies heretofore known have required the presence of an auxiliary means to dissipate heat generated in the hydraulic fluid as it is pumped and then used to energize motors for powering appliances. Such prior power supplies are positioned remote from the appliances, connected to the portable appliance by suitable hoses.
The heat generated by the hydraulic fluid must be dissipated effectively or power is reduced and equipment breakdown can result. Also, hydraulic power supplies have not been as compact and portable as the direct gasoline-driven tools such as slab saws. The interiors of some buildings and other enclosed areas have accordingly been inaccessible to hydraulic power supplies and tools and their advantages.